Beacon Headlight FAQ

What input power options are available?

    The Beacon can be powered by a dynamo, an external USB battery pack, or both.  An external USB battery can be connected using the barrel connector on the back of the light.  A USB-to-barrel cable is available.  The external battery will maintain high brightness and steady output, even when stopped.  When you begin riding, the power from the dynamo will begin to replace the power from the battery until you reach a speed where the dynamo is able to provide all of the power, and the battery is no longer used.  When you slow down the light resumes using the battery so the beam doesn't dim or flicker.

      How does the integrated USB charger work?

        The Beacon includes circuitry from our Revolution and Reactor chargers.  The USB output is available from a standard USB-A connector on the back of the light.  Connect your device directly to the USB port, or use a USB extension cable and put the connector anywhere you want.

          Is the USB charger always enabled?

            Yes.  The USB charger is enabled whether the light is on or off.  When the light is off, all the power from the dynamo can be used by the charger.  When the light is in Charger Priority Mode, a small amount of power will first be used by the light and the remainder will be available to the charger.  It is not recommended to use the charger while the light is in high brightness mode.

              What if I have limited clearance behind the headlight?

                We have space-saving right-angle cables available.  These cables also allow the wires to easily follow the mounting hardware for secure wire management.

                  What is Charger Priority Mode?

                    Other setups with a separate headlight and charger can do both at the same time, but the two devices are not designed to share power from the dynamo - the headlight can dim or flicker, depending on the power used by the charger, and the charger will require a faster speed to make up for the power used by the headlight.
                      Since the Beacon includes both the light and charger, they do a better job of working together.  Using Charger Priority Mode, the headlight will always maintain at least a reduced output - sufficient for a daytime running light or commuting on a lit street or path.  The charger gets priority to all remaining power, meaning your USB device will charge at much lower speeds because only a small, limited amount of power is used by the light.  Once sufficient power is available to the USB device, any additional power from the dynamo will be used by the light.  If your device is unplugged or done charging, all power will go to the light.

                          Can I charge the same battery that I use to power the light?

                          Yes.  Because the connectors on the battery are input only or output only, you'll need to connect two cables - a USB cable from the Beacon USB port to the battery input, and a USB-to-barrel from the battery output to the Beacon barrel connector.

                          You can either leave both cables connected or connect only one at a time, depending on whether you are using the charger or the light.

                          Are there multiple brightness settings?

                            Yes.  With the switch in the 'up' position, the battery will provide full brightness.  With the switch in the 'down' position, the battery will provide low brightness.  This can be used while riding but is also useful while setting up camp or making dinner.
                              When using the dynamo the light output is always maximized.  The brightness settings only affect the power used from the external battery.

                                How long will a battery last when powering the light?

                                On high the Beacon will draw about 800mA from the battery, or 4W.  On low, the Beacon will draw about 150mA, or 0.8W.

                                To determine battery life you'll need to know the capacity of your battery pack.  They are usually rated in mAh or Wh. 

                                If rated in Wh the battery life will be approximately (battery Wh) / (Beacon W draw).  For example, a 15Wh battery will last for about 15/4 = 3.75 hours on high, and 15/0.8 = 18.75 hours on low.

                                If rated in mAh, be aware that battery makers use the internal 3.7V battery voltage, rather than the 5V output voltage, which results in a higher number.  The math works out to (battery mAh) / (Beacon mA) x 3.7 / 5.  You are essentially converting to W and Wh and then following the math above.

                                Note that this calculates battery life when using only battery power.  When also using a dynamo the battery usage is greatly reduced, even at low speeds.  Actual battery life will depend on your speed but should be much longer than when using only a battery.

                                How bright is the light?

                                  Peak output when using dynamo power is 750 lumens.  A 700c/PV-8 wheel reaches this output at just 13 MPH.
                                    Battery powered output is 600/100 for High/Low.
                                      Dynamo power is optimized at low-to-medium speeds, providing much more light in this range than any other headlight.  The Beacon provides 200 lumens at 5 MPH, 500 lumens at 8 MPH, and 650 lumens at 10 MPH. 

                                            What shape is the beam?

                                              The beam is round/symmetrical.  This makes the Beacon an ideal choice for bikepacking, mountain biking, or any offroad riding.  The Beacon can be used on-road as well.

                                                Can I use a dynamo taillight?

                                                  Yes, the Beacon includes a taillight output wire.  The taillight is controlled by the headlight, turning on and off along with the headlight.

                                                  Note that the taillight output is only powered by the dynamo.  The taillight will not be powered when using only the external battery input.

                                                  The Beacon is compatible with taillights that do not ground to the bicycle frame.  See this page for more information.  Contact us if you have questions about a particular taillight.

                                                    Is there a standlight?

                                                      Yes.  A supercapacitor is charged while riding and will provide more than 5 minutes of "be seen" light when stopped.
                                                        The standlight cannot be turned off - it will continue to illuminate the light, even if the light is switched off.
                                                          If using an external USB battery the light will use the battery and remain at the selected High/Med/Low brightness level indefinitely.
                                                            The supercapacitor is only changed from the dynamo.  The external battery will not charge the supercapacitor.  This is typically preferred as the battery itself provides power when stopped.  It also allows the light to be switched completely off when using only battery power.

                                                              Is the Beacon waterproof?

                                                                Yes, the Beacon can be used in the rain and can be left outside.

                                                                  How is the Beacon so waterproof with open connectors?

                                                                    Multiple seals on the lens side protect against water ingress.  On the connector side, all connectors are designed for resistance to the elements, and the electronics are potted in epoxy.

                                                                      How do I install the Beacon on my bicycle?

                                                                        The 10mm mounting tab is compatible with mounting hardware from B&M, Supernova, Schmidt, etc.  There are options for mounting to the fork crown, handlebars, fork blade/dropout, front rack, and other locations.  We also have a GoPro adapter available.

                                                                          Can I install the Beacon upside-down?

                                                                            Yes.  The beam is symmetrical so there will not be any optical problems if the light is mounted upside down.  There is a small drainage hole in both the top and bottom of the light so water ingress will not be a problem.

                                                                              Can I replace the dynamo wire?

                                                                              The dynamo wire is soldered and potted in place inside the Beacon so it can not be removed and replaced.  In case of damage or a wire that has been cut too short we recommend splicing on a new section of wire or adding quick-release connectors.

                                                                              Do you have any recommended USB battery packs?

                                                                              When using a USB battery to power the Beacon, a maximum output current of at least 1A is recommended.  Any modern battery pack should be able to provide this.
                                                                                Most USB battery packs are very flexible and do a great job charging from the Beacon, even at low speed.  If you simply want to charge a battery while riding and use it later to charge your devices, almost any battery pack can be used.
                                                                                  If you want to use your battery like a buffer, and connect from Beacon to battery and battery to USB device, you need a battery that supports 'pass through charging'.  This feature is not always clearly advertised and is implemented differently by different brands. 

                                                                                    What if I have a question that isn't answered here?

                                                                                    Please email us at